The objectives of this project are the elucidation of the site and mechanism of action of 3, 4-dihydroxybutyl-1-phosphonate. Three approaches are being followed: (1) A study of the metabolism of the analogue of glycerol 3-phosphate by Escherichia coli and other organisms in vivo; (2) The in vitro examination of relevant enzymes; and (3) The isolation and characterization of resistant mutants.